Initial commit to get things going

This is just a starting point for the command line interface. It uses
the standard argparse library, and this seems to do what I need so far.
It may not be the ideal choice for the kind of interface I want to
provide (something like the aws-cli project), but I'll work within its
constraints, since I don't want to have to do any of my own parsing in
this respect.
Add gitignore
Add requirements for virtualenv
Fix some linting
Add mock and nosetest dependencies
Add empty init files

They're only empty for the time being.
Add base command

This will most likely be expanded further.
Starting implementation of command parser

For now, it just returns a single command. The test case that's
implemented here will also probably change to something more elaborate.
Provide a little bit of documentation
Test command is instance of
Basic implementation of cd ripping